Fluid not flowing straight
It looks as though the resolution of your fluid simulation is too coarse. Generally, the fluid can only interact properly with the obstacles if the resolution is fine enough that the significant details of the obstacles can be detected.
The &quot;Resolution Divisions&quot; parameter in the domain settings gives you control over this.
The challenge is to make the number of divisions high enough that all obstacles and boundaries are correctly recognized but small enough to keep baking times and memory manageable...
The &quot;multiple fluids&quot;-issue you mention is only a problem if you need different fluids with different properties (e.g. honey and oil) in the same scene. As they can not really interact with each other this way, that's a somewhat advanced topic requiring quite a bit of trickery.
Fortunately, different bodies of the same fluid (as in your case) are not a problem for the simulation.